Simulation and experiment of six-bed PSA process for air separation with rotating distribution valve

In this work,a six-bed pressure swing adsorption(PSA)process was investigated to produce medical oxygen from air,which uses the combination of six-way rotating distribution valve and PSA and has the main advantage of effectively saving space compared to the traditional two-bed or four-bed PSA process and can obtain greater productivity.The mathematical model of adsorption beds was developed based on the separation mechanism and the interaction among different equipment.Moreover,a pilot-scale device has been constructed to verify the accuracy of mathematical model by experiment.The oxygen product conformed to the medical standard(>93%(vol))with a recovery of over 57%.Some related parameters were also discussed in detail,such as step time,ratio of length to the diameter,flow rate of product.

隔离病房内呼吸道传染性疾病气溶胶吸入感染风险

医疗机构的院内感染给患者、医护人员和国家造成了巨大的健康和社会经济损失.气溶胶可以携带多种致病微生物,是院内感染的重要传播途径.量化确定医疗机构内的病原微生物浓度与感染风险对于减少院感发生和应对新发突发传染病具有重要意义.本研究以新型冠状病毒(severe acute respiratory syndrome coronavirus 2,SARSCoV-2)为例,针对医院隔离病房,将计算流体动力学(computational fluid dynamics,CFD)与定量微生物风险评估(quantitative microbial risk assessment,QMRA)相结合,建立了气溶胶传播感染风险定量评估模型.基于该模型,计算了隔离病房空气中的病毒浓度,定量评估了医护人员的吸入感染风险,分析了活动强度、个人防护、病毒变异、感染者个体差异等因素对感染风险的影响.结果表明,病房内的感染风险分布具有明显的空间异质性;吸入感染风险与个人活动强度和防护情况密切相关,高活动强度下的感染风险能达到中等活动强度的2倍左右;使用N95口罩可明显降低医护人员的吸入感染风险,无防护状态下的吸入感染风险是使用N95口罩时的3~10倍;毒株变异和个体差异会对感染风险产生明显影响,应该密切关注并及时调整防控策略.研究结果可以为医疗机构的感染防控提供理论依据和技术支持.